Cross instance user authentication architecture

ABSTRACT

In accordance with disclosed embodiments, there are provided methods, systems, and apparatuses for implementing a cross instance user authentication architecture in an on-demand service environment including, for example, means for receiving a login request at a global Virtual Internet Protocol (VIP) address for the host organization from a client device; forwarding the login request received at the global VIP address to one of a plurality of datacenters within the host organization; determining the selected datacenter is a non-home-geo datacenter for a user associated with the login request received from the client device; establishing a back-end link from the non-home-geo datacenter to a home-geo datacenter for the user; forwarding the login request from the non-home-geo datacenter to the home-geo datacenter via the back-end link for authentication of the client device at the home-geo datacenter responsive to the login request received from the computing device; and returning a response to the client device from the non-home-geo datacenter upon successful authentication of the login request at the home-geo datacenter, wherein the response specifies a re-direct to the home-geo datacenter for the user. Other related embodiments are disclosed.

CLAIM OF PRIORITY

This application is related to, and claims priority to, the provisionalutility application entitled “CROSS INSTANCE USER AUTHENTICATIONARCHITECTURE,” filed on Apr. 17, 2012, having an application number of61/625,194 and attorney docket No. 841PROV, the entire contents of whichare incorporated herein by reference.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

TECHNICAL FIELD

Embodiments relate generally to the field of computing, and moreparticularly, to systems, methods, and apparatuses for implementing across instance user authentication architecture in an on-demand serviceenvironment.

BACKGROUND

The subject matter discussed in the background section should not beassumed to be prior art merely as a result of its mention in thebackground section. Similarly, a problem mentioned in the backgroundsection or associated with the subject matter of the background sectionshould not be assumed to have been previously recognized in the priorart. The subject matter in the background section merely representsdifferent approaches, which in and of themselves may also correspond tothe claimed embodiments.

Within an on-demand service environment it is necessary to authenticateusers before allowing them to access any particular data repository soas to ensure the user possesses the appropriate credentials. This isgenerally referred to as the user log in process.

From an infrastructure point of view the user log in process may behandled via centralized log in servers which are dedicated to handlingthe authentication process. Such a model is less complex but alsoprovides for a single point of failure which may be catastrophic to aservices provider.

Alternatively, a distributed model may be utilized such that computingresources throughout the service provider's infrastructure perform userauthentication for the user log in process, but the distributed approachhas conventionally required replication of users so as to enable thedisparate non-centralized servers to handle such requests without havingto reference or communicate with a single centralized repository as partof the user log in process.

Unfortunately, replicating users is problematic because users areglobally unique, and thus, replication of users for the sake of adistributed authentication model violates the requirement that any givenuser be globally unique within such a system.

The present state of the art may therefore benefit from methods,systems, and apparatuses for implementing a cross instance userauthentication architecture as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example, and not by way oflimitation, and will be more fully understood with reference to thefollowing detailed description when considered in connection with thefigures in which:

FIG. 1A depicts an exemplary process flow in accordance with describedembodiments;

FIG. 1B depicts further processing in accordance with describedembodiments;

FIG. 2A depicts an exemplary architecture in accordance with describedembodiments;

FIG. 2B depicts an alternative exemplary architecture in accordance withdescribed embodiments;

FIG. 3 depicts an alternative exemplary architectural overview of theenvironment in which embodiments may operate;

FIG. 4 is a flow diagram illustrating a method in accordance withdisclosed embodiments;

FIG. 5 illustrates a diagrammatic representation of a machine in theexemplary form of a computer system, in accordance with one embodiment;

FIG. 6 illustrates a block diagram of an example of an environment inwhich an on-demand database service might be used; and

FIG. 7 illustrates a block diagram of an embodiment of elements of FIG.6 and various possible interconnections between these elements.

DETAILED DESCRIPTION

Described herein are systems, devices, and methods for implementing across instance user authentication architecture in an on-demand serviceenvironment.

In one embodiment, such means include: receiving a login request at aglobal Virtual Internet Protocol (VIP) address for the host organizationfrom a client device; forwarding the login request received at theglobal VIP address to one of a plurality of datacenters within the hostorganization; determining the selected datacenter is a non-home-geodatacenter for a user associated with the login request received fromthe client device; establishing a back-end link from the non-home-geodatacenter to a home-geo datacenter for the user; forwarding the loginrequest from the non-home-geo datacenter to the home-geo datacenter viathe back-end link for authentication of the client device at thehome-geo datacenter responsive to the login request received from thecomputing device; and returning a response to the client device from thenon-home-geo datacenter upon successful authentication of the loginrequest at the home-geo datacenter, in which the response specifies are-direct to the home-geo datacenter for the user.

In the following description, numerous specific details are set forthsuch as examples of specific systems, languages, components, etc., inorder to provide a thorough understanding of the various embodiments. Itwill be apparent, however, to one skilled in the art that these specificdetails need not be employed to practice the embodiments disclosedherein. In other instances, well known materials or methods have notbeen described in detail in order to avoid unnecessarily obscuring thedisclosed embodiments.

In addition to various hardware components depicted in the figures anddescribed herein, embodiments further include various operations whichare described below. The operations described in accordance with suchembodiments may be performed by hardware components or may be embodiedin machine-executable instructions, which may be used to cause ageneral-purpose or special-purpose processor programmed with theinstructions to perform the operations. Alternatively, the operationsmay be performed by a combination of hardware and software.

Embodiments also relate to an apparatus for performing the operationsdisclosed herein. This apparatus may be specially constructed for therequired purposes, or it may be a general purpose computer selectivelyactivated or reconfigured by a computer program stored in the computer.Such a computer program may be stored in a computer readable storagemedium, such as, but not limited to, any type of disk including floppydisks, optical disks, CD-ROMs, and magnetic-optical disks, read-onlymemories (ROMs), random access memories (RAMs), EPROMs, EEPROMs,magnetic or optical cards, or any type of media suitable for storingelectronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct more specializedapparatus to perform the required method steps. The required structurefor a variety of these systems will appear as set forth in thedescription below. In addition, embodiments are not described withreference to any particular programming language. It will be appreciatedthat a variety of programming languages may be used to implement theteachings of the embodiments as described herein.

Embodiments may be provided as a computer program product, or software,that may include a machine-readable medium having stored thereoninstructions, which may be used to program a computer system (or otherelectronic devices) to perform a process according to the disclosedembodiments. A machine-readable medium includes any mechanism forstoring or transmitting information in a form readable by a machine(e.g., a computer). For example, a machine-readable (e.g.,computer-readable) medium includes a machine (e.g., a computer) readablestorage medium (e.g., read only memory (“ROM”), random access memory(“RAM”), magnetic disk storage media, optical storage media, flashmemory devices, etc.), a machine (e.g., computer) readable transmissionmedium (electrical, optical, acoustical), etc.

Any of the disclosed embodiments may be used alone or together with oneanother in any combination. Although various embodiments may have beenpartially motivated by deficiencies with conventional techniques andapproaches, some of which are described or alluded to within thespecification, the embodiments need not necessarily address or solve anyof these deficiencies, but rather, may address only some of thedeficiencies, address none of the deficiencies, or be directed towarddifferent deficiencies and problems where are not directly discussed.

FIG. 1A depicts an exemplary process flow 100 in accordance withdescribed embodiments. In particular, process flow 100 depictsprocessing that may occur when a user attempts a login from aweb-browser. Other login requests may also be handled by such a flow,including performing authentication for SAML (Security Assertion MarkupLanguage) type logins, OATH (initiative for Open AuTHentication) typelogins, customer portal type logins, API (Application ProgrammingInterface) based logins, as well as others.

In an on-demand service environment, implementation of a distributedauthentication model overcomes certain problems associated with acentralized authentication utilized by some service providers. Forinstance, though a centralized authentication model is less technicallycomplex, it is vulnerable to catastrophic failure for the serviceprovider because it provides a single point of failure. For instance,whether due to a malicious attack such as a DDOS (Distributed Denial OfService) attack against the authentication means for the serviceprovider, service outages owing to system hardware failures,infrastructure damage incurred as the result of a natural disaster atthe geographic location of the datacenter, or even software andmaintenance problems with the authentication means, any problem whichmakes the centralized authentication unavailable to users renders theentire suite of services provided by the service provider inaccessibleand thus useless. Such an outage may even result from ordinary usage inwhich an unexpected peak demand occurs resulting in slowed or failedauthentications as contention and re-try attempts cause system thrashingand further exacerbate the problem.

A distributed authentication model on the other hand permits the systemto overcome these issues by, for example, servicing authenticationrequests at an alternative location when an initial location suffers anyof the above mentioned anomalies. Additionally, such a distributedauthentication model permits further computing resources to bedynamically applied on an as-needed basis by allocating additionalresources to authentication requests during peak periods and thende-allocating such resources from performing authentication serviceswhen they are no longer required.

At FIG. 1A, there is depicted a web-browser 199 which may operate at aclient device and there are further depicted a load balancer 198 and alogin server 197, each of which may operate within a host organization,such as at a datacenter having computational resources therein forperforming various operations including supporting authentication andlogin processes.

In this example, processing begins with block 105 in which a user entersa username and password into a web-browser 199, for instance, bynavigating to a login landing page for a given service provider, such asthe fictitious but exemplary https://login.serviceprovider.com. Theusername and password are then passed as depicted at block 110. Forinstance, the username and password may be passed via the publicInternet to a host organization operating as the service provider, andmore specifically, passed to a load balancer 198 which then selects aninstance from a login server pool as is indicated block 115.

Processing then advances to the login server 197 in which, for eachserver in that instance's login pool, processing looks up the usernameand password in the database for all instances in the present datacenteras indicated at block 120. For instance, a host organization may havemultiple datacenters distributed geographically, and processing looks upall instances in the particular datacenter at which processing is beinghandled.

At decision point 125 it is determined whether the username is on theparticular instance selected. If yes, then processing advances to block145 where the server ID for the instance having the username isreturned. If no, the username is not on that instance, then processingadvances to decision point 130.

At decision point 130 it is determined whether the username is inanother instance of the present datacenter. Such a determination is madeby the first instance performing a fan-out call to all other instanceswithin the present datacenter. If yes, the username is in anotherinstance of the present datacenter, then processing advances to block145 where the server ID for the instance having the username isreturned. If no, the username is not in another instance of the presentdatacenter, then processing advances to decision point 135.

At decision point 135 it is determined whether the username is on aselected instance at a remote datacenter. For instance, the hostorganization having multiple datacenters distributed geographically maythus cause the instance in first datacenter handling the presentprocessing to select an instance at a remote datacenter, so as to querywhether the username exists at that remote datacenter's instance. Ifyes, the username is on the selected instance at the remote datacenter,then processing advances to block 145 where the server ID for theinstance at the remote datacenter having the username is returned. Ifno, the username is not on the selected instance at the remotedatacenter, then processing advances to decision point 140.

At decision point 140 it is determined whether the username is on anyother instance of the remote datacenter. For example, just as with thefirst datacenter handling the processing for the initially receivedusername and password, an instance at the remote datacenter may beselected when necessary and then that selected instance at the remotedatacenter will perform a fan-out call to all the other instances withinthe remote datacenter to determine if any other instance at the remotedatacenter possesses the username specified. Moreover, this process maybe triggered at each of multiple remote datacenters for the hostorganization where more than two datacenters exist. If yes, the usernameis in another instance of the remote datacenter, then processingadvances to block 145 where the server ID for the instance having theusername is returned. If no, the username is not found at any otherinstance of the remote datacenter, then processing advances to block 150where an error code is generated indicating the username is not foundand the error code is then returned back to the web-browser 199 havinginitiated the login processing. The described instances may correspondto computing pods of the respective datacenters, in which each computingpod includes a local database instance and a pool of application serversby which workload on behalf of the host organization may be performed.Each datacenter may include a plurality of such instances or computingpods, each of which may need to be checked to determine if the specifiedusername is presently known to the host organization.

FIG. 1B depicts further processing 101 in accordance with describedembodiments. In particular, the further processing 101 is performedbased on the returned server ID from block 145 of FIG. 1A when theusername is found.

Processing begins with the server ID being passed to the applicationserver 196 as is indicated by block 146. The server ID corresponding tothe one returned via processing at block 145 of FIG. 1A. The server IDmay represent a particular computing pod within a datacenter, anapplication server pool within a datacenter, or a specific computingdevice within such an application server pool of a datacenter.

Within the application server 196, valid credentials arrive at theinstance home in the datacenter which is associated with the usernameand password, as indicated by block 165. For example, a user may beassociated with a datacenter organization having a geographicphysicality in San Francisco, near the user who resides in or around theSan Francisco area. If the same user visits New York City on the eastcoast, then such a user's request may initially be routed to adatacenter nearer to New York City than the one in San Francisco. Oncethe user's username is identified by a particular instance, the user'scredentials will be sent to the instance home at the San Franciscodatacenter which is associated with the user account residing withinthat instance. In such a way, it is not necessary to replicate the userto the datacenter near New York City because authentication processingmay take place at the home instance in the San Francisco datacenter oncethe login request is routed appropriately.

Processing continues at block 170 in which the application server 196performs an internal SOAP (Simple Object Access Protocol) call, or othersatisfactory call, to validate the username passed, validate an InternetProtocol (IP) address associated with the user's request, validatepermissions for the user against login hours permitted for the usernamespecified, and optionally issue further authentication challenges wherenecessary.

At block 175, a temporary session is created and a re-direct istriggered to the correct home instance for the username specified asdescribed above, for instance, by triggering a re-direct from thedatacenter near New York City back to the user's home instance in thedatacenter located in San Francisco.

Consider for example, a user opening a web-browser 199 and navigating tologin.serviceprovider.com. A load balancer 198 responsible for handlingsuch requests may select datacenter NA1 (North America #1) for handlingthe request based on geographic proximity to the user making the requestor based on resource availability, or based on server load. Regardlessof how NA1 is selected, an application server 196 at the NA1 datacenterlooks up the username specified as described previously and determinesthat username is not at NA1 but rather, is at NA6 (e.g., North America#6). The application server 196 at the NA1 datacenter thus makes across-instance call to the NA6 datacenter to perform authentication forthe user making the request based on the specified username beingassociated with the NA6 datacenter. Subsequent to successfulauthentication of the login request by the NA6 datacenter theapplication server at the NA1 datacenter returns a redirect URL (e.g.,specifying https://na6.serviceprovider.com/redirect?sid=encoded_value)to the user requesting the login instructing the user's web-browser 199to utilize the specified URL to communicate further with the hostorganization via an authenticated session between the user's web-browserand the specified NA6 datacenter (e.g., the NA1 datacenter responds tothe user's web-browser 199 with a redirect specifying the NA6 datacentervia the re-direct URL).

At block 180, the temporary session ID is validated and a valid sessioncookie is created when the temporary session ID is determined validresulting in the authenticated session to be used for furthercommunications between the user's web-browser and the host organization.The application server 196 creates the session cookie and sends it tothe user's web-browser 199 as part of the login response. According toone embodiment, the session cookie is instance specific and contains thefollowing: (a) A routing hint which is then used by the load balancer198 to aid in determining to which application server instance therequest should be routed. Such information may be stored within asession ID as follows: SessionKey.prependUnencodedLoadBalancerHint( ).The session cookie may further include (b) a session ID which iscomposed of a base64-encoded random key with checksum in which therandom key is a unique key to the session database table.

Processing then causes the session cookie to be passed at block 185 andthe user's web-browser 199 receives the session cookie at the browserhaving made the initial request as is indicated by block 190.

The user's web-browser 199 receives the session cookie and stores it inbrowser memory for the duration of the browser session or until thesession times out. A session ID within the session cookie is sent witheach request after a successful login. The browser uses the domain valueof the session cookie to determine whether to send the cookie or not.For example, if the session domain is set to na6.serviceprovider.comresponsive to a re-direct or otherwise, then the session ID will be sentwhen the current request is https://na1.serviceprovider.com. Conversely,the user's web-browser 199 won't send the session ID for any otherdomain.

If the session ID is not sent with the request then it is treated as anunauthenticated request. When an application server receives a sessioncookie with a request, it ignores the routing hint and it decodes thesession ID from base64 to text; validates the checksum; evaluates therandom key portion of the session ID, which is the primary key to thesession table on the database; and compares the session ID to the valuestored in the session table to validate it. These values may also becached so that a database query is not needed. Once the session ID isvalidated, additional validation is performed, such as making sure thecurrent IP address matches the one used to create the session andverifying that the session hasn't expired yet, and so forth.

By looking up the username in a selected instance, any login server isable to determine the actual user's instance and corresponding home-geodatacenter, regardless of whether such an instance is within the presentdatacenter processing the login request or at a remote datacenter. Ifthe user's instance is different than the one handling the originallogin request then a separate cross-instance login call may be initiatedto the correct instance based on a server ID returned via the processingdescribed earlier at FIG. 1A, regardless of whether the correct instanceis another computing pod within the same datacenter or at a remotedatacenter. For an unknown username, additional username discovery maybe initiated by making fan out calls first to the other instances withinthe same datacenter first and then to one or remote datacenters. Ifstill no username is found, then an error code is triggered and acounter is maintained for that requestor's IP as a means to protectagainst DOS or brute force attacks. For instance, if the bad usernameattempts exceed a threshold limit, then all subsequent user loginattempts from the same IP are rejected without any attemptedauthentication for at least a period of time. For example, the countermay be reduced gradually or reset after a time period of inactivity. Inan optional embodiment, a check is conducted to determine if replicationof a users table is behind, delayed, or out of synch, and if so, thenthe fan-out operations described are permitted, but if all such userstables are fully synchronized then it is not necessary to check otherlocal instances replicated throughout a datacenter because a localusername query miss will equate to a miss for the entire datacenter.Similarly, where a master users table is replicated globally across alldatacenters then local miss will equate to a global miss on a usernamewhen replication is up to date, thus negating the need to conduct remotefan-out operations to the geographically dispersed datacenters of thehost organization.

When a user is identified as valid but being processed at the wronginstance (e.g., not at the user's home-geo datacenter) then an internalcross-instance login call is triggered. For instance, a separate crossinstance login request is initiated to the correct user instance at theuser's home-geo datacenter. If the user instance is inside the samedatacenter as the original login request but at a different computingpod than the one performing the initial processing, then traffic maystay internal to a single datacenter without going outside thedatacenter's firewall. Conversely, if the user instance is on a remotedatacenter from the one initially executing the authentication scheme,then the cross instance communication may occur within a secure directconnection implemented as a back-end link between datacenters, forinstance, using secure HTTP tunneling, etc. A back-end link on theprivate network between datacenters of the host organization is fast andsecure and will thus reduce latency experienced by the user inprocessing the authentication request, regardless of which datacenterreceives the user's initial request.

FIG. 2A depicts an exemplary architecture 200 in accordance withdescribed embodiments. In particular, a client computing device 205having a web browser 210 is depicted at a home geographic location. Forinstance, a user who resides in San Jose, Calif. may have their datastored at a datacenter NA1 260 in nearby San Francisco, and thus, beassociated with or affiliated with datacenter NA1 given the proximity tothe users' home geographic location. Datacenter NA2 265 and datacenterNA3 270 are additionally depicted, but only datacenter NA1 is the homegeographic location for the exemplary user in this example.

A host organization may have multiple such datacenters (e.g., 260, 265,and 270) and for any given user, their user data will be stored withinone of the datacenters but not all. It may prove cost prohibitive toreplicate a user's data across all datacenters and it may additionallybe wasteful to do so because user's may rarely or never attempt toaccess their user data from most of the alternative datacenter locationsfor the host organization. Accordingly, a user's data is stored at ahome geographic location which is generally in close geographicproximity to where a user spends most of their time. This home-geodatacenter is also where each respective users' credentials are storedand thus where authentication processing responsive to a login requestwill take place. Notably, a users table which specifies all valid usersfor a given datacenter may be replicated throughout such a datacenter ora master users table specifying all users known to the host organizationand the corresponding home-geo datacenter for each user may bereplicated across all datacenters so as to aid in routing a user'srequest to the correct datacenter associated with the user's homegeography when a login request is received at a non-home geographydatacenter.

Further depicted at FIG. 2A is a request from the browser being sent toa Virtual Internet Protocol (VIP) address as indicated at element 290.Such a request may be communicated through the public Internet 220 to aURL end-point using a global virtual IP 255 (e.g., such aslogin.serviceprovider.com) which thus enables a user anywhere in theworld to access a single login page, regardless of their presentlocation or their home location.

A virtual IP address is an IP address assigned to multiple applicationsresiding on a single server, multiple domain names, or multiple servers,rather than being assigned to a specific single server or networkinterface card (NIC). Incoming data packets are sent to the VIP addresswhich are routed to actual network interfaces. A server IP addressdepends on the MAC address of the attached NIC, and only one logical IPaddress may be assigned per card. However, VIP addressing enableshosting for several different applications and virtual appliances on aserver with only one logical IP address. VIPs have several variationsand implementation scenarios, including Common Address RedundancyProtocol (CARP) and Proxy Address Resolution Protocol (Proxy ARP).virtual IP addresses are commonly used for connection redundancy byproviding alternative fail-over options in which a virtual IP addressremains available even when a computer or NIC fails, because analternative computer or NIC replies to incoming connection requests.Here, the virtual IP address further negates the need to specify aparticular datacenter among a plurality of available datacenters of thehost organization, thus allowing users to specify a single URL end-pointsuch as login.serviceprovider.com rather than having to specify, forexample, na1.login.serviceprovider.com to access the login interface ata first datacenter or na2.login.serviceprovider.com to access the logininterface at a different datacenter.

A geo-IP routing procedure 256 is next executed which identifies themost appropriate datacenter to service the request from the browser 290based on the present geographic location of the client computing device205. For instance, if the client computing device 205 is presently usingan IP address in the San Jose Calif. area then a datacenter near the SanJose Calif. area will be selected. Conversely, if the client computingdevice 205 is presently using an IP address in the New York City areathen a datacenter nearer to New York City will be selected to handle therequest 290 from the browser, regardless to the user's home geography.

In this particular example, the client computing device is indicated asoperating at its home geography, and as such, the geo-IP routingprocedure 256 selects datacenter NA1 260 to handle the request 290,which is also the datacenter at the home-geo for the user. The geo-IProuting procedure 256 then forwards the request to the geo-appropriatedatacenter selected as indicated by element 291.

Because the request is forwarded to the home-geo for the user atdatacenter 260, the username is recognized as belonging to thedatacenter NA1 260 and authentication processing 261 commences atdatacenter NA1 260. Upon successful authentication of the user based on,for example, a passed username, password, as well as other conditionssuch as time of use, IP verification, further authentication challenges,and so forth, a valid session cookie 292 will be returned to the clientcomputing device 205. The valid session cookie 292 may then be utilizedby the client computing device 205 to make further requests forservices, resources, access stored data, and so forth.

Because the user's client computing device 205 is located in thehome-geo and authentication processing occurred at the datacenter NA1260 associated with the user's home-geo it is not necessary to send are-direct to the web-browser.

The exemplary single login endpoint at login.serviceprovider.comprovides a login authentication service which is accessible via thesingle URL without being tied to the actual instance where anyparticular user's home-geo datacenter is located. A user may thereforelogin to the service from outside of a home-geo and yet still utilizethe single login endpoint. The Geo-IP routing procedure 256 running at aglobal load balancer will analyze the incoming request and thenselectively route the request to the data center and login server poolsgeographically near the user for quick access and improved performance,regardless of how far the user travels from the home geographyassociated with the particular user.

FIG. 2B depicts an alternative exemplary architecture 201 in accordancewith described embodiments. In particular, a client computing device 206having a web browser 210 is depicted at a non-home geographic location.For instance, a user who resides in San Jose, Calif. may have traveledto New York City, and thus, the client computing device 206 will beutilizing an IP address from the New York City area rather than the SanJose, Calif. area.

In such an example, the user's client computing device 206 neverthelessutilizes the same URL end-point which is using the global virtual IP255, for instance, by navigating the web browser 210 to the exemplarylogin.serviceprovider.com, just as with the previous example. However,the geo-IP routing procedure at 256 will forward the request to ageo-appropriate datacenter as indicated by element 291 and thus forwardthe request to the datacenter NA2 265 which, in this example, is in theNYC non-home-geo area for this particular user. The request is forwardedto the NYC area datacenter because it is assessed as being the mostappropriate to service the user's request 290, regardless of where theuser's home location may be.

Processing at the selected datacenter NA2 265 will identify datacenterNA1 260 as the home-geo for the specified user using the processingdescribed at FIG. 1A. Rather than reject the user, processing at thedatacenter NA2 265 opens a back-end link 275 between the datacenter NA1260 which is the home-geo for the user and the datacenter NA2 265 whichreceived the request due to its closer geographic proximity with theuser's client computing device 206.

The back-end link 275 is created using a compatible tunneling protocoland operates much faster between the two datacenters 260 and 265 thanwhat the client computing device 206 may attain by communicating withthe now geographically distant datacenter 260 through the publicInternet 220. The back-end link of the host organization between its owndatacenters is of a greater quality and speed than what is generallyavailable to the client computing device 206 in a geographically distantlocation from the home-geo datacenter 260.

A temporary session is requested via the back-end link 275 through whichthe username and password are then passed to the home-geo datacenter NA1260 associated with the user and then authentication processing 261occurs at the user's home-geo datacenter NA1 260. In one embodiment, theback-end link 275 is created using a secure HTTP tunneling protocol. Inanother embodiment, calls through the back-end link 275 are wrapped in anew secure request with a MAC in the header to protect againstmodification en-route through the back-end link 275. For instance, theMAC may operate as a hash on the input. In yet another embodiment, IPrestriction is applied to prevent external parties from accessing ormodifying calls being communicated through the back-end link 275 betweendatacenters 260 and 265.

Upon successful authentication using the temporary session and callsbetween the datacenters via the back-end link 275, a re-direct andsession cookie is returned to the client computing device 206 asindicated by element 293. Once the client computing device 206 receivesthe session cookie and is re-directed to communicate through the publicInternet 220 with its home-geo datacenter (e.g., datacenter NA1 260 inthis example), the client computing device 206 will then direct itsfurther communications to the home-geo datacenter 260 via anauthentication session using the session cookie returned 293. Forinstance, the client computing device, subsequent to successfulauthentication and receipt of the returned session cookie 293, initiateauthenticated requests to its home-geo datacenter as depicted by element294.

Using such a technique, even where a user specifies a login interface ata particular datacenter, such as na1.login.serviceprovider.com, a userwill still end up being re-directed to their home-geo datacenter for anauthenticated session using the session cookie returned, assuming thedatacenter NA1 260 specified by the URL is not the home-geo for theuser. This may occur, for example, where a user's data has been migratedto a different datacenter and is thus affiliated with a newhome-geography datacenter than the one specified by the user and perhapsdifferent from the datacenter familiar to the user having specified thenon-geo datacenter via the datacenter specific URL.

When an API client sends a login( ) request, the client device sends theusername and password to the global Virtual IP Interface, for instance,by sending the request to a URL located athttp://login.serviceprovider.com, which may be identical to theinterface utilized by the browser interface described previously.

Unlike browser based requests, the API requests are given a permanentsession ID and as such, operations related to temporary session IDs areomitted. Such an authentication mechanism may be applied to anyinfrastructure having multiple servers inside a single datacenter ormultiple servers provisioned across multiple datacenters.

In certain embodiments, properties of original request are maintained,such as the IP address for the requesting client device. Wherecross-instance calls are initiated on behalf of a client being processedat a non-home-geo location, the receiving application server may viewthe cross-instance call as a request from another internal server, butthe request is actually being made on behalf of the original requestingclient device. Accordingly, an HTTP header may be added to suchcross-instance calls specifying the original client IP such that anotherserver receiving a cross-instance call may read out the header todetermine the originating client's IP address, rather than the IPaddress of the application server initiating the cross-instance call.

FIG. 3 depicts an alternative exemplary architectural overview 300 ofthe environment in which embodiments may operate. In particular, thereare depicted multiple customer organizations 305A, 305B, and 305C.Obviously, there may be many more customer organizations than thosedepicted. In the depicted embodiment, each of the customer organizations305A-C includes at least one client device 306A, 306B, and 306C. A usermay be associated with such a client device, and may further initiaterequests 315 to the host organization 310 which is connected with thevarious customer organizations 305A-C and client devices 306A-C vianetwork 325 (e.g., such as via the public Internet).

According to one embodiment, the client devices 306A-C each include aweb-browser 307 in support of the various methodologies describedherein. The client devices 306A-C each individually transmit requests315 to the remote host organization 310 via the network 325. The hostorganization 310 may responsively send responses 316 to the originatingcustomer organization to be received via the respective client devices306A-C and their supporting web-browsers 307.

Within host organization 310 is a global Virtual IP (VIP) interface andload balancer 380 which provides a single login point regardless ofwhere a user's client device 306A-C is operating geographically. Theglobal Virtual IP (VIP) interface and load balancer 380 facilitatesreceipt of initial authentication requests and selection of anapplication server instance to begin processing of the authenticationrequests. Subsequent authenticated requests may bypass the globalVirtual IP (VIP) interface and load balancer 380 and be directed to aspecific datacenter or may be directed to a datacenter specific loadbalancer which receives authenticated requests and then selectsresources from the application server pools (e.g., 362 and 365) oravailable pods (e.g., 361, 364, 372, 373, 376, and 377) to conductfurther processing.

In one embodiment, each of the respective datacenters 360, 370, and 375constitute resources of a single host organization 310 which provideson-demand cloud based services. Datacenters (e.g., 360, 370, and 375) ofthe host organization 310 may be distributed globally. For instance,datacenter NA1 360 may be in California within North America, datacenterNA2 may be in the New York City area of North America, and datacenterEU1 375 may be in London servicing the European region. Additionaldatacenters and different localities may be utilized. Each of therespective datacenters (e.g., 360, 370, and 375) of the hostorganization 310 may include multiple computing pods (e.g., 361, 364,372, 373, 376, and 377), in which each pod includes a database and apool of application servers that may be utilized for authenticationservices as well as other computing tasks. For instance, datacenter NA1360 is depicted with such detail in which pod 361 includes database 363as well as a pool of application servers 362 and pod 364 includesdatabase 366 as well as a pool of application servers 365. Datacenters370 and 375 may implement a similar internal structure. The applicationservers may be allocated and de-allocated from computing tasksdynamically so as to meet the demand from users for computing resourcesof the host organization 310. For instance, additional applicationservers may be dynamically allocated to provide authentication servicesas demand for authentication increases, and then de-allocated whendemand for authentication decreases.

In one embodiment, each datacenter may optionally include a local loadbalancer 371 which is capable to receive requests from the globalVirtual IP (VIP) interface and load balancer 380 and distribute suchworkload requests amongst pods within the datacenter (e.g., pod 372 and373 at datacenter NA2 370) and select instances from application serverpools within the datacenter which are to receive such workload requests.

In one embodiment, a users table 378 is replicated amongst all podswithin a single datacenter (e.g., 375) but is not replicated to otherdatacenters (e.g., 360 and 370), and thus, users tables at each of thedatacenters is unique to each particular datacenter. For example, userstable 378 is depicted as being replicated amongst pods 376 and 377within the datacenter EU1 at element 375. In a different embodiment, amaster users table is synchronized and replicated across all datacenters(e.g., 360, 370, and 375) of the host organization 310 and furtherspecifies a home-geo datacenter for each respective user within themaster users table. For instance, master users table 379 is shown beingreplicated from the datacenter EU1 at element 375 to each of datacenters360 and 365. Such replication may be performed in each direction asrequired.

In one embodiment, new users are created within a single pod of adatacenter and are synchronized to the other pods and optionally to theremaining datacenters. In such an embodiment, an authentication requestat a pod of a datacenter does not trigger a failure when the user is notfound, but instead, causes a fan-out request to be triggered to firstquery other pods within the same datacenter for the user's instance andthen subsequently triggers a cross-call fan-out request to one or moreremote datacenters to query for the user's instance at the remotedatacenters. If the user's instance cannot be identified at anydatacenter, local or otherwise, then the request results in an error. Ifthe user's instance is identified at a remote datacenter, then theauthentication request is processed as described previously.

Thus, in accordance with one embodiment, there is a computingarchitecture within a host organization, the computing architectureincluding: one or more processors and memories to execute instructions;a plurality of datacenters geographically separated from one another,each of the plurality of datacenters having a plurality of computingpods therein including a database and a pool of application servers toperform workload processing on behalf of the host organization; a globalvirtual IP address interface and load balancer servicing a single URLendpoint for the host organization to receive login requests on behalfof the host organization; in which the global virtual IP addressinterface and load balancer is to receive a login request from a clientdevice and forward the login request to one of the plurality ofdatacenters within the host organization; in which an application serverat the selected datacenter determines the selected datacenter is anon-home-geo datacenter for a user associated with the login requestreceived from the client device; in which the application serverestablishes a back-end link from the non-home-geo datacenter to anotherapplication server at a home-geo datacenter for the user and forwardsthe login request from the non-home-geo datacenter to the home-geodatacenter via the back-end link for authentication of the client deviceat the home-geo datacenter responsive to the login request received fromthe computing device; and in which the application server at thenon-home-geo datacenter returns a response to the client device uponsuccessful authentication of the login request by the other applicationserver at the home-geo datacenter, in which the response specifies are-direct to the home-geo datacenter for the user.

According to another embodiment of the computing architecture, each ofthe plurality of datacenters further includes a local load balancer todistribute workload amongst the plurality of computing pods applicationservers within each of the respective plurality of datacenters.

FIG. 4 is a flow diagram illustrating a method 400 in accordance withdisclosed embodiments. Method 400 may be performed by processing logicthat may include hardware (e.g., circuitry, dedicated logic,programmable logic, microcode, etc.), software (e.g., instructions runon a processing device to perform various operations such transmitting,sending, receiving, monitoring, recording, updating, calculating, etc.,in pursuance of the systems, apparatuses, and methods for implementing across instance user authentication architecture, as described herein.For example, the web-browser, load balancer, and login server of FIG. 1Amay implement the described methodologies. Some of the blocks and/oroperations listed below are optional in accordance with certainembodiments. The numbering of the blocks presented is for the sake ofclarity and is not intended to prescribe an order of operations in whichthe various blocks must occur.

At block 405, processing logic receives a login request from a clientdevice at a global Virtual Internet Protocol (VIP) address of a hostorganization.

At block 410, processing logic forwards the login request received atthe global VIP address to one of a plurality of datacenters within thehost organization.

At block 415, processing logic determines the selected datacenter is anon-home-geo datacenter for a user associated with the login requestreceived from the client device.

At block 420, processing logic establishes a back-end link from thenon-home-geo datacenter to a home-geo datacenter for the user.

At block 425, processing logic forwards the login request from thenon-home-geo datacenter to the home-geo datacenter via the back-end linkfor authentication of the client device at the home-geo datacenterresponsive to the login request received from the computing device.

At block 430, processing logic returns a response to the client devicefrom the non-home-geo datacenter upon successful authentication of thelogin request at the home-geo datacenter, in which the responsespecifies a re-direct to the home-geo datacenter for the user.

According to another embodiment of the method 400, receiving a loginrequest at a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device includes: receiving the login requestat a single URL endpoint servicing login requests for the hostorganization at the Virtual IP address specified regardless of thehome-geo datacenter affiliated with incoming login requests.

According to another embodiment of the method 400, receiving a loginrequest at a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device includes receiving the login requestat a global Virtual IP interface and load balancer for the hostorganization; and in which the global Virtual IP interface and loadbalancer selects the one of the plurality of datacenters within the hostorganization to process the login request received based on a geographicproximity of the client device making the login request and the selectedone of the plurality of datacenters.

According to another embodiment of the method 400, the global Virtual IPinterface and load balancer operates at computing hardware of the hostorganization which resides outside of the selected one of the pluralityof datacenters and which resides outside of the home-geo datacenter forthe user.

According to another embodiment of the method 400, the global Virtual IPinterface and load balancer selects an instance from an applicationserver pool at the selected datacenter to receive the login request forfurther processing.

According to another embodiment of the method 400, forwarding the loginrequest received at the global VIP address to one of a plurality ofdatacenters within the host organization, includes: forwarding the loginrequest to a local load balancer at the selected one of the plurality ofdatacenters, in which the local load balancer selects an instance froman application server pool within the selected datacenter to receive thelogin request for further processing.

According to another embodiment of the method 400, forwarding the loginrequest from the non-home-geo datacenter to the home-geo datacenter viathe back-end link, includes: determining a geographic region associatedwith the client device based on an Internet Protocol (IP) address forthe client device; and performing geographic Internet Protocol (Geo-IP)routing for the client device based on the geographic region associatedwith the client device to select the one of a plurality of datacenterswithin the host organization.

According to another embodiment of the method 400, determining theselected datacenter is a non-home-geo datacenter for a user associatedwith the login request received from the client device, includes:receiving the login request at an application server within a firstcomputing pod of the selected datacenter; checking a database within thefirst computing pod for a username passed with the login request;performing a fan-out operation to a second one or more computing podswithin the selected datacenter requesting application servers in therespective second one or more computing pods check databases within therespective second one or more computing pods for the username passedwith the login request when the username is not located in the databaseof the first computing pod; and performing a fan-out operation to asecond one or more datacenters of the host organization distinct fromthe selected datacenter requesting application servers in the respectivesecond one or more datacenters check databases within the respectivesecond one or more datacenters for the username passed with the loginrequest when the username is not located in any of the computing pods ofthe selected datacenter.

According to another embodiment the method 400 further includes:returning an error code to the computing device making the login requestwhen the username is not identified within any datacenter of the hostorganization indicating the user is unknown or invalid; maintaining acount of invalid requests associated with computing device making thelogin request; and discarding further login requests from the computingdevice to protect against denial of service (DOS) attacks when the countof invalid requests from the computing device exceeds a threshold.

According to another embodiment the method 400 further includes one of:replicating a users table across all pods within individual datacentersof the host organization but not across multiple datacenters of the hostorganization, in which the users table specifies all users affiliatedwith the respective datacenter as their home-geo datacenter; oralternatively replicating a master users table across all datacenters ofthe host organization, in which the master users table specifies allusers known to the host organization and the home-geo datacenter foreach of the users known.

According to another embodiment the method 400 further includes:replicating a master users table across all datacenters of the hostorganization, in which the master users table specifies users associatedwith the host organization and the affiliated home-geo datacenter foreach user; and in which the method further includes: determining a userassociated with the login request received from the client device isunknown to the host organization after querying a single database at theselected datacenter when replication of the master users table isup-to-date, and determining the user associated with the login requestreceived from the client device is unknown to the host organizationafter querying multiple databases within the selected datacenter andafter querying all other datacenters of the host organization viafan-out operations when replication of the master users table is notup-to-date.

According to another embodiment the method 400 further includes:replicating a users table within the selected datacenter of the hostorganization, in which the users table specifies all users associatedwith the selected datacenter as their affiliated home-geo datacenter;and in which the method further includes: determining the selecteddatacenter is a non-home-geo datacenter for the user associated with thelogin request received from the client device after querying a singledatabase at the selected datacenter when replication of the users tableis up-to-date, and performing a fan-out operation to other datacentersof the host organization to determine which of the plurality ofdatacenters is the home-geo for the user associated with the loginrequest received.

According to another embodiment of the method 400, receiving a loginrequest at a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device includes receiving the login requestfrom a web-browser at the client device; in which establishing aback-end link from the non-home-geo datacenter to a home-geo datacenterfor the user further includes communicating with the home-geo datacenterover the back-end link using a temporary session; and in which returninga response to the client device from the non-home-geo datacenter uponsuccessful authentication of the login request at the home-geodatacenter further includes returning a valid session cookie for anauthenticated session between the client device and the home-geodatacenter specified via the re-direct.

According to another embodiment of the method 400, receiving a loginrequest at a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device includes receiving an API based loginrequest from the client device. Such a method further includesestablishing a session for the API based login request; in whichestablishing a back-end link from the non-home-geo datacenter to ahome-geo datacenter for the user further includes communicating with thehome-geo datacenter over the back-end link using the session for the APIbased login request; and in which returning a response to the clientdevice from the non-home-geo datacenter upon successful authenticationof the login request at the home-geo datacenter further includesauthenticating the session for the API based login request and returninga valid session cookie for the authenticated session for use between theclient device and the home-geo datacenter specified via the re-direct.

According to another embodiment of the method 400, authentication of theclient device at the home-geo datacenter responsive to the login requestreceived from the computing device includes: validating a username andpassword passed with the login request.

According to another embodiment of the method 400, authentication of theclient device further includes: validating an Internet Protocol (IP)address associated with the user's login request; validating the useragainst permissible login hours for the username specified; andvalidating a challenge response to a further authentication challengeissued by the host organization responsive to the login request.

According to another embodiment of the method 400, establishing aback-end link from the non-home-geo datacenter to a home-geo datacenterfor the user includes opening a secure HTTP compatible tunnel between anapplication server instance of the non-home-geo datacenter and anapplication server instance at the home-geo datacenter.

According to another embodiment of the method 400, forwarding the loginrequest from the non-home-geo datacenter to the home-geo datacenter viathe back-end link comprises communicating cross-instance calls betweenthe non-home-geo datacenter and the home-geo datacenter, wherein each ofthe cross-instance calls are secured by one or more of the following: atemporary session ID created uniquely for the communications between thenon-home-geo datacenter and the home-geo datacenter in fulfillment ofthe login request; a header specifying a hash of the MAC address of theinstance at the non-home-geo datacenter to protect against modificationto the cross-instance calls en-route; and IP restriction applied to thecross-instance calls on the back-end link to prevent external partiesfrom accessing or modifying the cross-instance calls being communicated.

According to another embodiment the method 400 further includes:receiving the login request at the host organization as one of aplurality of requests received from a plurality of customerorganizations, in which each customer organization is an entity selectedfrom the group consisting of: a separate and distinct remoteorganization, an organizational group within the host organization, abusiness partner of the host organization, or a customer organizationthat subscribes to cloud computing services provided by the hostorganization.

According to another embodiment of the method 400, the host organizationimplements a multi-tenant database system having therein elements ofhardware and software that are shared by a plurality of separate anddistinct customer organizations, each of the separate and distinctcustomer organizations being remotely located from the datacenters ofthe host organization and in which the customer organizationscommunicate with the host organization over a public Internet.

According to one embodiment, there is a non-transitory computer readablestorage medium storage medium having instructions stored thereon that,when executed by a computing hardware of a host organization includingone or more processors and memories, the instructions cause the hostorganization to perform operations comprising: receiving a login requestat a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device; forwarding the login request receivedat the global VIP address to one of a plurality of datacenters withinthe host organization; determining the selected datacenter is anon-home-geo datacenter for a user associated with the login requestreceived from the client device; establishing a back-end link from thenon-home-geo datacenter to a home-geo datacenter for the user;forwarding the login request from the non-home-geo datacenter to thehome-geo datacenter via the back-end link for authentication of theclient device at the home-geo datacenter responsive to the login requestreceived from the computing device; and returning a response to theclient device from the non-home-geo datacenter upon successfulauthentication of the login request at the home-geo datacenter, in whichthe response specifies a re-direct to the home-geo datacenter for theuser.

In another embodiment of the non-transitory computer readable storagemedium, receiving a login request at a global Virtual Internet Protocol(VIP) address for the host organization from a client device includes:receiving the login request at a single URL endpoint servicing loginrequests for the host organization at the Virtual IP address specifiedregardless of the home-geo datacenter affiliated with incoming loginrequests.

In another embodiment of the non-transitory computer readable storagemedium, forwarding the login request from the non-home-geo datacenter tothe home-geo datacenter via the back-end link, includes: determining ageographic region associated with the client device based on an InternetProtocol (IP) address for the client device; performing geographicInternet Protocol (Geo-IP) routing for the client device based on thegeographic region associated with the client device to select the one ofa plurality of datacenters within the host organization.

FIG. 5 illustrates a diagrammatic representation of a machine 500 in theexemplary form of a computer system, in accordance with one embodiment,within which a set of instructions, for causing the machine/computersystem 500 to perform any one or more of the methodologies discussedherein, may be executed. In alternative embodiments, the machine may beconnected (e.g., networked) to other machines in a Local Area Network(LAN), an intranet, an extranet, or the public Internet. The machine mayoperate in the capacity of a server or a client machine in aclient-server network environment, as a peer machine in a peer-to-peer(or distributed) network environment, as a server or series of serverswithin an on-demand service environment. Certain embodiments of themachine may be in the form of a personal computer (PC), a tablet PC, aset-top box (STB), a Personal Digital Assistant (PDA), a cellulartelephone, a web appliance, a server, a network router, switch orbridge, computing system, or any machine capable of executing a set ofinstructions (sequential or otherwise) that specify actions to be takenby that machine. Further, while only a single machine is illustrated,the term “machine” shall also be taken to include any collection ofmachines (e.g., computers) that individually or jointly execute a set(or multiple sets) of instructions to perform any one or more of themethodologies discussed herein.

The exemplary computer system 500 includes a processor 502, a mainmemory 504 (e.g., read-only memory (ROM), flash memory, dynamic randomaccess memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM(RDRAM), etc., static memory such as flash memory, static random accessmemory (SRAM), volatile but high-data rate RAM, etc.), and a secondarymemory 518 (e.g., a persistent storage device including hard disk drivesand a persistent database and/or a multi-tenant databaseimplementation), which communicate with each other via a bus 530. Mainmemory 504 includes a global virtual IP interface at element 524, aglobal load balancer at element 525, and local load balancer(s) atelement 523, for instance, one being local to each of a plurality ofdatacenters as described previously. Main memory 504 and itssub-elements are operable in conjunction with processing logic 526 andprocessor 502 to perform the methodologies discussed herein.

Processor 502 represents one or more general-purpose processing devicessuch as a microprocessor, central processing unit, or the like. Moreparticularly, the processor 502 may be a complex instruction setcomputing (CISC) microprocessor, reduced instruction set computing(RISC) microprocessor, very long instruction word (VLIW) microprocessor,processor implementing other instruction sets, or processorsimplementing a combination of instruction sets. Processor 502 may alsobe one or more special-purpose processing devices such as an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA), a digital signal processor (DSP), network processor, or thelike. Processor 502 is configured to execute the processing logic 526for performing the operations and functionality which is discussedherein.

The computer system 500 may further include a network interface card508. The computer system 500 also may include a user interface 510 (suchas a video display unit, a liquid crystal display (LCD), or a cathoderay tube (CRT)), an alphanumeric input device 512 (e.g., a keyboard), acursor control device 514 (e.g., a mouse), and a signal generationdevice 516 (e.g., an integrated speaker). The computer system 500 mayfurther include peripheral device 536 (e.g., wireless or wiredcommunication devices, memory devices, storage devices, audio processingdevices, video processing devices, etc.).

The secondary memory 518 may include a non-transitory machine-readableor computer readable storage medium 531 on which is stored one or moresets of instructions (e.g., software 522) embodying any one or more ofthe methodologies or functions described herein. The software 522 mayalso reside, completely or at least partially, within the main memory504 and/or within the processor 502 during execution thereof by thecomputer system 500, the main memory 504 and the processor 502 alsoconstituting machine-readable storage media. The software 522 mayfurther be transmitted or received over a network 520 via the networkinterface card 508.

FIG. 6 illustrates a block diagram of an example of an environment 610in which an on-demand database service might be used. Environment 610may include user systems 612, network 614, system 616, processor system617, application platform 618, network interface 620, tenant datastorage 622, system data storage 624, program code 626, and processspace 628. In other embodiments, environment 610 may not have all of thecomponents listed and/or may have other elements instead of, or inaddition to, those listed above.

Environment 610 is an environment in which an on-demand database serviceexists. User system 612 may be any machine or system that is used by auser to access a database user system. For example, any of user systems612 may be a handheld computing device, a mobile phone, a laptopcomputer, a work station, and/or a network of computing devices. Asillustrated in FIG. 6 (and in more detail in FIG. 7) user systems 612might interact via a network 614 with an on-demand database service,which is system 616.

An on-demand database service, such as system 616, is a database systemthat is made available to outside users that do not need to necessarilybe concerned with building and/or maintaining the database system, butinstead may be available for their use when the users need the databasesystem (e.g., on the demand of the users). Some on-demand databaseservices may store information from one or more tenants stored intotables of a common database image to form a multi-tenant database system(MTS). Accordingly, “on-demand database service 616” and “system 616” isused interchangeably herein. A database image may include one or moredatabase objects. A relational database management system (RDMS) or theequivalent may execute storage and retrieval of information against thedatabase object(s). Application platform 618 may be a framework thatallows the applications of system 616 to run, such as the hardwareand/or software, e.g., the operating system. In an embodiment, on-demanddatabase service 616 may include an application platform 618 thatenables creation, managing and executing one or more applicationsdeveloped by the provider of the on-demand database service, usersaccessing the on-demand database service via user systems 612, or thirdparty application developers accessing the on-demand database servicevia user systems 612.

The users of user systems 612 may differ in their respective capacities,and the capacity of a particular user system 612 might be entirelydetermined by permissions (permission levels) for the current user. Forexample, where a salesperson is using a particular user system 612 tointeract with system 616, that user system has the capacities allottedto that salesperson. However, while an administrator is using that usersystem to interact with system 616, that user system has the capacitiesallotted to that administrator. In systems with a hierarchical rolemodel, users at one permission level may have access to applications,data, and database information accessible by a lower permission leveluser, but may not have access to certain applications, databaseinformation, and data accessible by a user at a higher permission level.Thus, different users will have different capabilities with regard toaccessing and modifying application and database information, dependingon a user's security or permission level.

Network 614 is any network or combination of networks of devices thatcommunicate with one another. For example, network 614 may be any one orany combination of a LAN (local area network), WAN (wide area network),telephone network, wireless network, point-to-point network, starnetwork, token ring network, hub network, or other appropriateconfiguration. As the most common type of computer network in currentuse is a TCP/IP (Transfer Control Protocol and Internet Protocol)network, such as the global internetwork of networks often referred toas the “Internet” with a capital “I,” that network will be used in manyof the examples herein. However, it is understood that the networks thatthe claimed embodiments may utilize are not so limited, although TCP/IPis a frequently implemented protocol.

User systems 612 might communicate with system 616 using TCP/IP and, ata higher network level, use other common Internet protocols tocommunicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTPis used, user system 612 might include an HTTP client commonly referredto as a “browser” for sending and receiving HTTP messages to and from anHTTP server at system 616. Such an HTTP server might be implemented asthe sole network interface between system 616 and network 614, but othertechniques might be used as well or instead. In some implementations,the interface between system 616 and network 614 includes load sharingfunctionality, such as round-robin HTTP request distributors to balanceloads and distribute incoming HTTP requests evenly over a plurality ofservers. At least as for the users that are accessing that server, eachof the plurality of servers has access to the MTS′ data; however, otheralternative configurations may be used instead.

In one embodiment, system 616, shown in FIG. 6, implements a web-basedcustomer relationship management (CRM) system. For example, in oneembodiment, system 616 includes application servers configured toimplement and execute CRM software applications as well as providerelated data, code, forms, webpages and other information to and fromuser systems 612 and to store to, and retrieve from, a database systemrelated data, objects, and Webpage content. With a multi-tenant system,data for multiple tenants may be stored in the same physical databaseobject, however, tenant data typically is arranged so that data of onetenant is kept logically separate from that of other tenants so that onetenant does not have access to another tenant's data, unless such datais expressly shared. In certain embodiments, system 616 implementsapplications other than, or in addition to, a CRM application. Forexample, system 616 may provide tenant access to multiple hosted(standard and custom) applications, including a CRM application. User(or third party developer) applications, which may or may not includeCRM, may be supported by the application platform 618, which managescreation, storage of the applications into one or more database objectsand executing of the applications in a virtual machine in the processspace of the system 616.

One arrangement for elements of system 616 is shown in FIG. 6, includinga network interface 620, application platform 618, tenant data storage622 for tenant data 623, system data storage 624 for system data 625accessible to system 616 and possibly multiple tenants, program code 626for implementing various functions of system 616, and a process space628 for executing MTS system processes and tenant-specific processes,such as running applications as part of an application hosting service.Additional processes that may execute on system 616 include databaseindexing processes.

Several elements in the system shown in FIG. 6 include conventional,well-known elements that are explained only briefly here. For example,each user system 612 may include a desktop personal computer,workstation, laptop, PDA, cell phone, or any wireless access protocol(WAP) enabled device or any other computing device capable ofinterfacing directly or indirectly to the Internet or other networkconnection. User system 612 typically runs an HTTP client, e.g., abrowsing program, such as Microsoft's Internet Explorer browser,Netscape's Navigator browser, Opera's browser, or a WAP-enabled browserin the case of a cell phone, PDA or other wireless device, or the like,allowing a user (e.g., subscriber of the multi-tenant database system)of user system 612 to access, process and view information, pages andapplications available to it from system 616 over network 614. Each usersystem 612 also typically includes one or more user interface devices,such as a keyboard, a mouse, trackball, touch pad, touch screen, pen orthe like, for interacting with a graphical user interface (GUI) providedby the browser on a display (e.g., a monitor screen, LCD display, etc.)in conjunction with pages, forms, applications and other informationprovided by system 616 or other systems or servers. For example, theuser interface device may be used to access data and applications hostedby system 616, and to perform searches on stored data, and otherwiseallow a user to interact with various GUI pages that may be presented toa user. As discussed above, embodiments are suitable for use with theInternet, which refers to a specific global internetwork of networks.However, it is understood that other networks may be used instead of theInternet, such as an intranet, an extranet, a virtual private network(VPN), a non-TCP/IP based network, any LAN or WAN or the like.

According to one embodiment, each user system 612 and all of itscomponents are operator configurable using applications, such as abrowser, including computer code run using a central processing unitsuch as an Intel Pentium® processor or the like. Similarly, system 616(and additional instances of an MTS, where more than one is present) andall of their components might be operator configurable usingapplication(s) including computer code to run using a central processingunit such as processor system 617, which may include an Intel Pentium®processor or the like, and/or multiple processor units.

According to one embodiment, each system 616 is configured to providewebpages, forms, applications, data and media content to user (client)systems 612 to support the access by user systems 612 as tenants ofsystem 616. As such, system 616 provides security mechanisms to keepeach tenant's data separate unless the data is shared. If more than oneMTS is used, they may be located in close proximity to one another(e.g., in a server farm located in a single building or campus), or theymay be distributed at locations remote from one another (e.g., one ormore servers located in city A and one or more servers located in cityB). As used herein, each MTS may include one or more logically and/orphysically connected servers distributed locally or across one or moregeographic locations. Additionally, the term “server” is meant toinclude a computer system, including processing hardware and processspace(s), and an associated storage system and database application(e.g., OODBMS or RDBMS) as is well known in the art. It is understoodthat “server system” and “server” are often used interchangeably herein.Similarly, the database object described herein may be implemented assingle databases, a distributed database, a collection of distributeddatabases, a database with redundant online or offline backups or otherredundancies, etc., and might include a distributed database or storagenetwork and associated processing intelligence.

FIG. 7 illustrates a block diagram of an embodiment of elements of FIG.6 and various possible interconnections between these elements. FIG. 7also illustrates environment 610. However, in FIG. 7, the elements ofsystem 616 and various interconnections in an embodiment are furtherillustrated. FIG. 7 shows that user system 612 may include a processorsystem 612A, memory system 612B, input system 612C, and output system612D. FIG. 7 shows network 614 and system 616. FIG. 7 also shows thatsystem 616 may include tenant data storage 622, tenant data 623, systemdata storage 624, system data 625, User Interface (UI) 730, ApplicationProgram Interface (API) 732, PL/SOQL 734, save routines 736, applicationsetup mechanism 738, applications servers 700 ₁-700 _(N), system processspace 702, tenant process spaces 704, tenant management process space710, tenant storage area 712, user storage 714, and application metadata716. In other embodiments, environment 610 may not have the sameelements as those listed above and/or may have other elements insteadof, or in addition to, those listed above.

User system 612, network 614, system 616, tenant data storage 622, andsystem data storage 624 were discussed above in FIG. 6. As shown by FIG.7, system 616 may include a network interface 620 (of FIG. 6)implemented as a set of HTTP application servers 700, an applicationplatform 618, tenant data storage 622, and system data storage 624. Alsoshown is system process space 702, including individual tenant processspaces 704 and a tenant management process space 710. Each applicationserver 700 may be configured to tenant data storage 622 and the tenantdata 623 therein, and system data storage 624 and the system data 625therein to serve requests of user systems 612. The tenant data 623 mightbe divided into individual tenant storage areas 712, which may be eithera physical arrangement and/or a logical arrangement of data. Within eachtenant storage area 712, user storage 714 and application metadata 716might be similarly allocated for each user. For example, a copy of auser's most recently used (MRU) items might be stored to user storage714. Similarly, a copy of MRU items for an entire organization that is atenant might be stored to tenant storage area 712. A UI 730 provides auser interface and an API 732 provides an application programmerinterface to system 616 resident processes to users and/or developers atuser systems 612. The tenant data and the system data may be stored invarious databases, such as one or more Oracle™ databases.

Application platform 618 includes an application setup mechanism 738that supports application developers' creation and management ofapplications, which may be saved as metadata into tenant data storage622 by save routines 736 for execution by subscribers as one or moretenant process spaces 704 managed by tenant management process space 710for example. Invocations to such applications may be coded using PL/SOQL734 that provides a programming language style interface extension toAPI 732. Invocations to applications may be detected by one or moresystem processes, which manages retrieving application metadata 716 forthe subscriber making the invocation and executing the metadata as anapplication in a virtual machine.

Each application server 700 may be communicably coupled to databasesystems, e.g., having access to system data 625 and tenant data 623, viaa different network connection. For example, one application server 700₁ might be coupled via the network 614 (e.g., the Internet), anotherapplication server 700 _(N-1) might be coupled via a direct networklink, and another application server 700 _(N) might be coupled by yet adifferent network connection. Transfer Control Protocol and InternetProtocol (TCP/IP) are typical protocols for communicating betweenapplication servers 700 and the database system. However, it will beapparent to one skilled in the art that other transport protocols may beused to optimize the system depending on the network interconnect used.

In certain embodiments, each application server 700 is configured tohandle requests for any user associated with any organization that is atenant. Because it is desirable to be able to add and remove applicationservers from the server pool at any time for any reason, there ispreferably no server affinity for a user and/or organization to aspecific application server 700. In one embodiment, therefore, aninterface system implementing a load balancing function (e.g., an F5Big-IP load balancer) is communicably coupled between the applicationservers 700 and the user systems 612 to distribute requests to theapplication servers 700. In one embodiment, the load balancer uses aleast connections algorithm to route user requests to the applicationservers 700. Other examples of load balancing algorithms, such as roundrobin and observed response time, also may be used. For example, incertain embodiments, three consecutive requests from the same user mayhit three different application servers 700, and three requests fromdifferent users may hit the same application server 700. In this manner,system 616 is multi-tenant, in which system 616 handles storage of, andaccess to, different objects, data and applications across disparateusers and organizations.

As an example of storage, one tenant might be a company that employs asales force where each salesperson uses system 616 to manage their salesprocess. Thus, a user might maintain contact data, leads data, customerfollow-up data, performance data, goals and progress data, etc., allapplicable to that user's personal sales process (e.g., in tenant datastorage 622). In an example of a MTS arrangement, since all of the dataand the applications to access, view, modify, report, transmit,calculate, etc., may be maintained and accessed by a user system havingnothing more than network access, the user may manage his or her salesefforts and cycles from any of many different user systems. For example,if a salesperson is visiting a customer and the customer has Internetaccess in their lobby, the salesperson may obtain critical updates as tothat customer while waiting for the customer to arrive in the lobby.

While each user's data might be separate from other users' dataregardless of the employers of each user, some data might beorganization-wide data shared or accessible by a plurality of users orall of the users for a given organization that is a tenant. Thus, theremight be some data structures managed by system 616 that are allocatedat the tenant level while other data structures might be managed at theuser level. Because an MTS might support multiple tenants includingpossible competitors, the MTS may have security protocols that keepdata, applications, and application use separate. Also, because manytenants may opt for access to an MTS rather than maintain their ownsystem, redundancy, up-time, and backup are additional functions thatmay be implemented in the MTS. In addition to user-specific data andtenant specific data, system 616 might also maintain system level datausable by multiple tenants or other data. Such system level data mightinclude industry reports, news, postings, and the like that are sharableamong tenants.

In certain embodiments, user systems 612 (which may be client systems)communicate with application servers 700 to request and updatesystem-level and tenant-level data from system 616 that may requiresending one or more queries to tenant data storage 622 and/or systemdata storage 624. System 616 (e.g., an application server 700 in system616) automatically generates one or more SQL statements (e.g., one ormore SQL queries) that are designed to access the desired information.System data storage 624 may generate query plans to access the requesteddata from the database.

Each database may generally be viewed as a collection of objects, suchas a set of logical tables, containing data fitted into predefinedcategories. A “table” is one representation of a data object, and may beused herein to simplify the conceptual description of objects and customobjects as described herein. It is understood that “table” and “object”may be used interchangeably herein. Each table generally contains one ormore data categories logically arranged as columns or fields in aviewable schema. Each row or record of a table contains an instance ofdata for each category defined by the fields. For example, a CRMdatabase may include a table that describes a customer with fields forbasic contact information such as name, address, phone number, faxnumber, etc. Another table might describe a purchase order, includingfields for information such as customer, product, sale price, date, etc.In some multi-tenant database systems, standard entity tables might beprovided for use by all tenants. For CRM database applications, suchstandard entities might include tables for Account, Contact, Lead, andOpportunity data, each containing pre-defined fields. It is understoodthat the word “entity” may also be used interchangeably herein with“object” and “table.”

In some multi-tenant database systems, tenants may be allowed to createand store custom objects, or they may be allowed to customize standardentities or objects, for example by creating custom fields for standardobjects, including custom index fields. In certain embodiments, forexample, all custom entity data rows are stored in a single multi-tenantphysical table, which may contain multiple logical tables perorganization. It is transparent to customers that their multiple“tables” are in fact stored in one large table or that their data may bestored in the same table as the data of other customers.

While the subject matter disclosed herein has been described by way ofexample and in terms of the specific embodiments, it is to be understoodthat the claimed embodiments are not limited to the explicitlyenumerated embodiments disclosed. To the contrary, the disclosure isintended to cover various modifications and similar arrangements as areapparent to those skilled in the art. Therefore, the scope of theappended claims are to be accorded the broadest interpretation so as toencompass all such modifications and similar arrangements. It is to beunderstood that the above description is intended to be illustrative,and not restrictive. Many other embodiments will be apparent to those ofskill in the art upon reading and understanding the above description.The scope of the disclosed subject matter is therefore to be determinedin reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

What is claimed is:
 1. A method at a host organization, the methodcomprising: receiving a login request at a global Virtual InternetProtocol (VIP) address for the host organization from a client device;forwarding the login request received at the global VIP address to oneof a plurality of datacenters within the host organization; determiningthe selected datacenter is a non-home-geo datacenter for a userassociated with the login request received from the client device;establishing a back-end link from the non-home-geo datacenter to ahome-geo datacenter for the user; forwarding the login request from thenon-home-geo datacenter to the home-geo datacenter via the back-end linkfor authentication of the client device at the home-geo datacenterresponsive to the login request received from the computing device; andreturning a response to the client device from the non-home-geodatacenter upon successful authentication of the login request at thehome-geo datacenter, wherein the response specifies a re-direct to thehome-geo datacenter for the user.
 2. The method of claim 1, whereinreceiving a login request at a global Virtual Internet Protocol (VIP)address for the host organization from a client device comprises:receiving the login request at a single URL endpoint servicing loginrequests for the host organization at the Virtual IP address specifiedregardless of the home-geo datacenter affiliated with incoming loginrequests.
 3. The method of claim 1: wherein receiving a login request ata global Virtual Internet Protocol (VIP) address for the hostorganization from a client device comprises receiving the login requestat a global Virtual IP interface and load balancer for the hostorganization; and wherein the global Virtual IP interface and loadbalancer selects the one of the plurality of datacenters within the hostorganization to process the login request received based on a geographicproximity of the client device making the login request and the selectedone of the plurality of datacenters.
 4. The method of claim 3, whereinthe global Virtual IP interface and load balancer operates at computinghardware of the host organization which resides outside of the selectedone of the plurality of datacenters and which resides outside of thehome-geo datacenter for the user.
 5. The method of claim 3, wherein theglobal Virtual IP interface and load balancer selects an instance froman application server pool at the selected datacenter to receive thelogin request for further processing.
 6. The method of claim 3, whereinforwarding the login request received at the global VIP address to oneof a plurality of datacenters within the host organization, comprises:forwarding the login request to a local load balancer at the selectedone of the plurality of datacenters, wherein the local load balancerselects an instance from an application server pool within the selecteddatacenter to receive the login request for further processing.
 7. Themethod of claim 1, wherein forwarding the login request from thenon-home-geo datacenter to the home-geo datacenter via the back-endlink, comprises: determining a geographic region associated with theclient device based on an Internet Protocol (IP) address for the clientdevice; and performing geographic Internet Protocol (Geo-IP) routing forthe client device based on the geographic region associated with theclient device to select the one of a plurality of datacenters within thehost organization.
 8. The method of claim 1, wherein determining theselected datacenter is a non-home-geo datacenter for a user associatedwith the login request received from the client device, comprises:receiving the login request at an application server within a firstcomputing pod of the selected datacenter; checking a database within thefirst computing pod for a username passed with the login request;performing a fan-out operation to a second one or more computing podswithin the selected datacenter requesting application servers in therespective second one or more computing pods check databases within therespective second one or more computing pods for the username passedwith the login request when the username is not located in the databaseof the first computing pod; and performing a fan-out operation to asecond one or more datacenters of the host organization distinct fromthe selected datacenter requesting application servers in the respectivesecond one or more datacenters check databases within the respectivesecond one or more datacenters for the username passed with the loginrequest when the username is not located in any of the computing pods ofthe selected datacenter.
 9. The method of claim 8, further comprising:returning an error code to the computing device making the login requestwhen the username is not identified within any datacenter of the hostorganization indicating the user is unknown or invalid; maintaining acount of invalid requests associated with computing device making thelogin request; and discarding further login requests from the computingdevice to protect against denial of service (DOS) attacks when the countof invalid requests from the computing device exceeds a threshold. 10.The method of claim 1, further comprising one of: replicating a userstable across all pods within individual datacenters of the hostorganization but not across multiple datacenters of the hostorganization, wherein the users table specifies all users affiliatedwith the respective datacenter as their home-geo datacenter; oralternatively replicating a master users table across all datacenters ofthe host organization, wherein the master users table specifies allusers known to the host organization and the home-geo datacenter foreach of the users known.
 11. The method of claim 1, further comprising:replicating a master users table across all datacenters of the hostorganization, wherein the master users table specifies users associatedwith the host organization and the affiliated home-geo datacenter foreach user; and wherein the method further comprises: determining a userassociated with the login request received from the client device isunknown to the host organization after querying a single database at theselected datacenter when replication of the master users table isup-to-date, and determining the user associated with the login requestreceived from the client device is unknown to the host organizationafter querying multiple databases within the selected datacenter andafter querying all other datacenters of the host organization viafan-out operations when replication of the master users table is notup-to-date.
 12. The method of claim 1, further comprising: replicating ausers table within the selected datacenter of the host organization,wherein the users table specifies all users associated with the selecteddatacenter as their affiliated home-geo datacenter; and wherein themethod further comprises: determining the selected datacenter is anon-home-geo datacenter for the user associated with the login requestreceived from the client device after querying a single database at theselected datacenter when replication of the users table is up-to-date,and performing a fan-out operation to other datacenters of the hostorganization to determine which of the plurality of datacenters is thehome-geo for the user associated with the login request received. 13.The method of claim 1: wherein receiving a login request at a globalVirtual Internet Protocol (VIP) address for the host organization from aclient device comprises receiving the login request from a web-browserat the client device; wherein establishing a back-end link from thenon-home-geo datacenter to a home-geo datacenter for the user furthercomprises communicating with the home-geo datacenter over the back-endlink using a temporary session; and wherein returning a response to theclient device from the non-home-geo datacenter upon successfulauthentication of the login request at the home-geo datacenter furthercomprises returning a valid session cookie for an authenticated sessionbetween the client device and the home-geo datacenter specified via there-direct.
 14. The method of claim 1: wherein receiving a login requestat a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device comprises receiving an API based loginrequest from the client device; wherein the method further comprisesestablishing a session for the API based login request; whereinestablishing a back-end link from the non-home-geo datacenter to ahome-geo datacenter for the user further comprises communicating withthe home-geo datacenter over the back-end link using the session for theAPI based login request; and wherein returning a response to the clientdevice from the non-home-geo datacenter upon successful authenticationof the login request at the home-geo datacenter further comprisesauthenticating the session for the API based login request and returninga valid session cookie for the authenticated session for use between theclient device and the home-geo datacenter specified via the re-direct.15. The method of claim 1, wherein authentication of the client deviceat the home-geo datacenter responsive to the login request received fromthe computing device comprises: validating a username and passwordpassed with the login request.
 16. The method of claim 15, whereinauthentication of the client device further comprises: validating anInternet Protocol (IP) address associated with the user's login request;validating the user against permissible login hours for the usernamespecified; and validating a challenge response to a furtherauthentication challenge issued by the host organization responsive tothe login request.
 17. The method of claim 1, wherein establishing aback-end link from the non-home-geo datacenter to a home-geo datacenterfor the user comprises opening a secure HTTP compatible tunnel betweenan application server instance of the non-home-geo datacenter and anapplication server instance at the home-geo datacenter.
 18. The methodof claim 1, wherein forwarding the login request from the non-home-geodatacenter to the home-geo datacenter via the back-end link comprisescommunicating cross-instance calls between the non-home-geo datacenterand the home-geo datacenter, wherein each of the cross-instance callsare secured by one or more of the following: a temporary session IDcreated uniquely for the communications between the non-home-geodatacenter and the home-geo datacenter in fulfillment of the loginrequest; a header specifying a hash of the MAC address of the instanceat the non-home-geo datacenter to protect against modification to thecross-instance calls en-route; and IP restriction applied to thecross-instance calls on the back-end link to prevent external partiesfrom accessing or modifying the cross-instance calls being communicated.19. The method of claim 1, further comprising: receiving the loginrequest at the host organization as one of a plurality of requestsreceived from a plurality of customer organizations, wherein eachcustomer organization is an entity selected from the group consistingof: a separate and distinct remote organization, an organizational groupwithin the host organization, a business partner of the hostorganization, or a customer organization that subscribes to cloudcomputing services provided by the host organization.
 20. The method ofclaim 19, wherein the host organization implements a multi-tenantdatabase system having therein elements of hardware and software thatare shared by a plurality of separate and distinct customerorganizations, each of the separate and distinct customer organizationsbeing remotely located from the datacenters of the host organization andwherein the customer organizations communicate with the hostorganization over a public Internet.
 21. Non-transitory computerreadable storage medium having instructions stored thereon that, whenexecuted by a computing hardware of a host organization including one ormore processors and memories, the instructions cause the hostorganization to perform operations comprising: receiving a login requestat a global Virtual Internet Protocol (VIP) address for the hostorganization from a client device; forwarding the login request receivedat the global VIP address to one of a plurality of datacenters withinthe host organization; determining the selected datacenter is anon-home-geo datacenter for a user associated with the login requestreceived from the client device; establishing a back-end link from thenon-home-geo datacenter to a home-geo datacenter for the user;forwarding the login request from the non-home-geo datacenter to thehome-geo datacenter via the back-end link for authentication of theclient device at the home-geo datacenter responsive to the login requestreceived from the computing device; and returning a response to theclient device from the non-home-geo datacenter upon successfulauthentication of the login request at the home-geo datacenter, whereinthe response specifies a re-direct to the home-geo datacenter for theuser.
 22. The non-transitory computer readable storage medium of claim21, wherein receiving a login request at a global Virtual InternetProtocol (VIP) address for the host organization from a client devicecomprises: receiving the login request at a single URL endpointservicing login requests for the host organization at the Virtual IPaddress specified regardless of the home-geo datacenter affiliated withincoming login requests.
 23. The non-transitory computer readablestorage medium of claim 21, wherein forwarding the login request fromthe non-home-geo datacenter to the home-geo datacenter via the back-endlink, comprises: determining a geographic region associated with theclient device based on an Internet Protocol (IP) address for the clientdevice; and performing geographic Internet Protocol (Geo-IP) routing forthe client device based on the geographic region associated with theclient device to select the one of a plurality of datacenters within thehost organization.
 24. A computing architecture within a hostorganization, the computing architecture comprising: one or moreprocessors and memories to execute instructions; a plurality ofdatacenters geographically separated from one another, each of theplurality of datacenters having a plurality of computing pods thereinincluding a database and a pool of application servers to performworkload processing on behalf of the host organization; a global virtualIP address interface and load balancer servicing a single URL endpointfor the host organization to receive login requests on behalf of thehost organization; wherein the global virtual IP address interface andload balancer is to receive a login request from a client device andforward the login request to one of the plurality of datacenters withinthe host organization; wherein an application server at the selecteddatacenter determines the selected datacenter is a non-home-geodatacenter for a user associated with the login request received fromthe client device; wherein the application server establishes a back-endlink from the non-home-geo datacenter to another application server at ahome-geo datacenter for the user and forwards the login request from thenon-home-geo datacenter to the home-geo datacenter via the back-end linkfor authentication of the client device at the home-geo datacenterresponsive to the login request received from the computing device; andwherein the application server at the non-home-geo datacenter returns aresponse to the client device upon successful authentication of thelogin request by the other application server at the home-geodatacenter, wherein the response specifies a re-direct to the home-geodatacenter for the user.
 25. The computing architecture of claim 24,wherein each of the plurality of datacenters further comprises a localload balancer to distribute workload amongst the plurality of computingpods application servers within each of the respective plurality ofdatacenters.